         mod-multipliers [2.5 0.5 1.5]
         pitch-with-kr (map #(overtone.sc.ugen-collide/+ freq (o/sin-osc:kr (overtone.sc.ugen-collide/* % mod-rate))) mod-multipliers)]
 
-    (overtone.sc.ugen-collide/+
+    (o/mix
         (map #(o/resonz (o/saw %) %2 q) pitch-with-kr eq-freq))))
 
 (defn synth-filter-chain

  []
  (o/synth [] (o/out 0 (o/sin-osc 440))))

(o/definst drone-eh-sus
  "I make the 'eh' vowel sound at a given frequency.
   I start/stop with the gate set to 1 or 0."
  [freq   80
   gate   (synth-defaults ::gate)
   amp    (synth-defaults ::vca)
   verb   (synth-defaults ::reverb)
   mod-rate-ctl 25]

  (let [mod-rate   (synth-defaults ::vco)
        eq-freq    [530 1840 2480]
        hpf-rlpf   [0 750 0.9]
        q          0.1
        synth-unit (synth-unit-layered freq eq-freq q mod-rate)]

    (synth-filter-chain synth-unit amp verb gate hpf-rlpf mod-rate-ctl)))

;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Rhythm               ;;

  "I create a stack of oscilators, each narrowly EQed on a given Q (frequency) to shape a saw waveform of a certain pitch.
   The end results are sharp Q spikes that resemble vowel formants like eh, aw, ae, etc...

   Step one is created a stack of pitches, all tuned to a fundamental frequency (the freq parameter)
   The frequency is modulated (the mod-rate parameter) by the control rate (0hz = no modulation)
   The mod-rate parameter is adjusted by an array of mod-multipliers (3 mod-multipliers = three voices)
   Note: the freq and mod-rate parameters are not integers, they are overtone.sc.machinery.ugen.sc_ugen.ControlProxy
         coming from the definst macro, therefore the * must be overtone.sc.ugen-collide/*

   ex: (synth-unit-layered 200 [530 1840 2480] 0.1 25)
   --> (#<sc-ugen: binary-op-u-gen:ar [4]> #<sc-ugen: binary-op-u-gen:ar [4]> #<sc-ugen: binary-op-u-gen:ar [4]>)"

